(a) Field of the Invention
The present invention concerns a pickup arm controlling apparatus for use in an automatic audio record or video disk player arranged so that, as a result of the detection of a particular portion of the groove formed on a disk which is located between adjacent pieces of signal recorded thereon or a lead-in groove (hereinafter such portion of groove will be called non-signal carrying portion of groove), a reproduction of an audio or a video signal can be performed automatically at such a desired specific portion of the groove, and the present invention features the arrangement enabling the stylus of a pickup to descend exactly onto the position at which a desired piece of signal is to be started by compensating for an overshooting of the pickup arm when it is caused to be brought to a lead-in position.
(b) Description of the Prior Art
There have been known automatic audio record or video disk players which are designed to perform the reproduction of an arbitrarily designated piece of music or image recorded on a disk. One such example utilizes the difference in intensity of the light rays reflected from the portion of groove which carries, for example, a music signal, relative to the light beam reflected from the groove carrying no signal recorded, when a beam light is irradiated onto a disk. Such conventional player, for example an audio record player, is arranged so that a photo-coupler is incorporated in a headshell to detect a non-recorded portion of the groove located immediately before a designated number of piece of music to thereby start this desired number of music. Also, another conventional arrangement utilizes similar reflection of light beam irradiated onto a disk, but this example is designed to automatically detect the specific radius of the groove at which the stylus is positioned on a disk, to thereby enable the reproduction from a lead-in groove. Any way, all of these conventional automatic audio record or video disk players are arranged so that, when a reproduction or play is to be intended, the pickup arm in its uplifted state is moved progressively toward the center of the disk supported on the turntable to detect a non-recorded portion of the groove, and that upon detection of the groove of the non-recorded portion located immediately prior to a designated piece of music or the groove of the initial non-recorded lead, a further driving of the pickup arm is suspended, and the arm is caused to descend onto the disk. However, even when the horizontal running of the pickup arm is applied with a braking force after the non-recorded portion of the groove has been detected, the pickup arm would make an unavoidable overshoot due to its inertia. Thus, the stylus will fail to descend onto the exact position for starting the desired reproduction, but will inconveniently descend onto such position which is located in the midst of the music signal-carrying or other signal-carrying groove portion. In order to prevent such inconvenience from arising, the lead-in velocity of the pickup arm has to be slowed down, which, in turn, consumes some length of time before a reproduction.